prising an area of probably 200,000 square miles. These facts have ex- 
isted too long and cover too much territory to be ascribed to local pecu- 
larities of soil or season. The wheat grower knows that fertilizers pay. 
But as brands multiplied the question arose which is the more profitable, 
and many made simple tests of different brands in which the popularity 
of the local agent received more consideration than the amount and kind 
of plant food in the goods: they obtained the confusing results that might 
have been expected under these conditions. Better informed farmers ap- 
plied to their experiment stations and agricultural colleges for aid, and 
in most cases were surprised to be told either that commercial plant foods 
did not pay or that they were unnecessary. 
An examination of the records of field tests conducted by experiment 
stations in the winter wheat section shows that many experiments have 
been made, especially on wheat, and that most of them have been reported 
unprofitable. This apparent conflict between the results of practical and 
scientific agriculture has to some extent prevented the extension of the 
sale of plant food to territory where it was very much needed. One may 
fairly inquire why the results of the experimental field tests differ so 
widely from the results obtained in ordinary farm practice in the same 
sections. 
First, we may consider certain things that are general in their nature. 
Many experiments are reported where relatively heavy applications of 
farm yard manure have been compared with applications of various brands 
and quantities of fertilizers without any clear statement or apparent 
knowledge of the composition of the latter. Such experiments are almost 
invariably reported as showing that manure is more profitable than the 
fertilizer, which is not strange in view of the fact that in the valuations 
the full cost of the fertilizer is charged up, while to the manure is charged 
only the cost of hauling. In such reports there is often a very clear inti- 
mation that the result is quite in line with the preconceived notions of 
the experimenter and that in discouraging the use of ‘expensive fertil- 
izers” he is at least telling farmers what they like to hear even though 
it conflicts with what they need to know. 
The method of application of the plant food is in many cases respon- 
sible for a considerable part of the difference observed between field prac- 
tice and plot experiments. Application with the drill at the time of sow- 
ing small grains, which is the common method, frequently gives profitable 
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